Wanting to Separate Modem/Router unit into 2 units

I can't stand Cox's modem/router combo units. Out of being too busy and lazy, I've stuck with one for a minute now but I simply can't anymore. I have 2 questions regarding this, 1) What is the process of separating the 2? Years ago I had to go to a Cox store and exchange it for the modem only and then set up my router separately. Is this still the case? Or is there a way to just have the unit function as a modem only? 2) If there is a way to change its settings so that it's modem only, what is the login information used for the web browser login? I have tried admin/admin, admin/password, nothing seems to work. Got in a chat with a rep from India who had no idea what I was even asking for to the point that he eventually stopped replying so I'm not even sure how to go about acquiring credentials. Thanks in advance!